Reason, we are told, is what makes us human, the source of our knowledge and wisdom. If reason is so useful, why didn't it also evolve in other animals? If reason is that reliable, why do we produce so much thoroughly reasoned nonsense? In their groundbreaking account of the evolution and workings of reason, Hugo Mercier and Dan Sperber set out to solve this double enigma. Reason, they argue with a compelling mix of real-life and experimental evidence, is (...) not geared to solitary use, to arriving at better beliefs and decisions on our own. What reason does, rather, is help us justify our beliefs and actions to others, convince them through argumentation, and evaluate the justifications and arguments that others address to us. In other words, reason helps humans better exploit their uniquely rich social environment. This interactionist interpretation explains why reason may have evolved and how it fits with other cognitive mechanisms. It makes sense of strengths and weaknesses that have long puzzled philosophers and psychologists--why reason is biased in favor of what we already believe, why it may lead to terrible ideas and yet is indispensable to spreading good ones.--. (shrink)

Humans massively depend on communication with others, but this leaves them open to the risk of being accidentally or intentionally misinformed. To ensure that, despite this risk, communication remains advantageous, humans have, we claim, a suite of cognitive mechanisms for epistemic vigilance. Here we outline this claim and consider some of the ways in which epistemic vigilance works in mental and social life by surveying issues, research and theories in different domains of philosophy, linguistics, cognitive psychology and the social sciences.

Much evidence has accumulated in favor of such a dual view of reasoning. There is however some vagueness in the way the two systems are characterized. Instead of a principled distinction, we are presented with a bundle of contrasting features - slow/fast, automatic/controlled, explicit/implicit, associationist/rule based, modular/central - that, depending on the specific dual process theory, are attributed more or less exclusively to one of the two systems. As Evans states in a recent review, “it would then be helpful to (...) have some clear basis for this distinction”; he also suggests that “we might be better off talking about type 1 and type 2 processes” rather than systems. We share the intuitions that drove the development of dual system theories. Our goal here is to propose in the same spirit a principled distinction between two types of inferences: ‘intuitive inference’ and ‘reflective inference’. We ground this distinction in a massively modular view of the human mind where metarepresentational modules play an important role in explaining the peculiarities of human psychological evolution. We defend the hypothesis that the main function of reflective inference is to produce and evaluate arguments occurring in interpersonal communication. This function, we claim, helps explain important aspects of reasoning. We review some of the existing evidence and argue that it gives support to this approach. (shrink)

Having defended the usefulness of our definition of reasoning, we stress that reasoning is not only for convincing but also for evaluating arguments, and that as such it has an epistemic function. We defend the evidence supporting the theory against several challenges: People are good informal arguers, they reason better in groups, and they have a confirmation bias. Finally, we consider possible extensions, first in terms of process-level theories of reasoning, and second in the effects of reasoning outside the lab.

In their reviews, Chater and Oaksford, Dutilh Novaes, and Sterelny are critical of our modularist approach to reason. In this response, we clarify our claim that reason is one of many cognitive modules that produce intuitive inferences each in its domain; the reason module producing intuitions about reasons. We argue that in‐principle objections to the idea of massive modularity based on Fodor's peculiar approach are not effective against other interpretations that have led to insightful uses of the notion in psychology (...) and biology. We explain how the reason module evaluates reasons on the basis of their metacognitive properties. We show how the module fulfils a social function, that of producing reasons to justify oneself and convince others and of evaluating the reasons others produce to convince us. (shrink)

Reasoning is generally seen as a means to improve knowledge and make better decisions. However, much evidence shows that reasoning often leads to epistemic distortions and poor decisions. This suggests that the function of reasoning should be rethought. Our hypothesis is that the function of reasoning is argumentative. It is to devise and evaluate arguments intended to persuade. Reasoning so conceived is adaptive given the exceptional dependence of humans on communication and their vulnerability to misinformation. A wide range of evidence (...) in the psychology of reasoning and decision making can be reinterpreted and better explained in the light of this hypothesis. Poor performance in standard reasoning tasks is explained by the lack of argumentative context. When the same problems are placed in a proper argumentative setting, people turn out to be skilled arguers. Skilled arguers, however, are not after the truth but after arguments supporting their views. This explains the notorious confirmation bias. This bias is apparent not only when people are actually arguing, but also when they are reasoning proactively from the perspective of having to defend their opinions. Reasoning so motivated can distort evaluations and attitudes and allow erroneous beliefs to persist. Proactively used reasoning also favors decisions that are easy to justify but not necessarily better. In all these instances traditionally described as failures or flaws, reasoning does exactly what can be expected of an argumentative device: Look for arguments that support a given conclusion, and, ceteris paribus, favor conclusions for which arguments can be found. (shrink)

The Pigeonhole Principle states that if n items are sorted into m categories and if n > m, then at least one category must contain more than one item. For instance, if 22 pigeons are put into 17 pigeonholes, at least one pigeonhole must contain more than one pigeon. This principle seems intuitive, yet when told about a city with 220,000 inhabitants none of whom has more than 170,000 hairs on their head, many people think that it is merely likely (...) that two inhabitants have the exact same number of hair. This failure to apply the Pigeonhole Principle might be due to the large numbers used, or to the cardinal rather than nominal presentation of these numbers. We show that performance improved both when the numbers are presented nominally, and when they are small, albeit less so. We discuss potential interpretations of these results in terms of intuition and reasoning. (shrink)

The role of reasoning in our moral lives has been increasingly called into question by moral psychology. Not only are intuitions guiding many of our moral judgments and decisions, with reasoning only finding post-hoc rationalizations, but reasoning can sometimes play a negative role, by finding excuses for our moral violations. The observations fit well with the argumentative theory of reasoning (Mercier H, Sperber D, Behav Brain Sci, in press-b), which claims that reasoning evolved to find and evaluate arguments (...) in dialogic contexts. This theory explains the strong confirmation bias that reasoning displays when it produces arguments, which in turn explains its tendency to rationalize our decisions. But this theory also predicts that people should be able to evaluate arguments felicitously and that, as a result, people should reason better in groups, when they are confronted with other people’s arguments. Groups are able to converge on better moral judgments. It is argued that reasoning and argumentation play an important role in our everyday moral lives, and a defense of the value of reasoning for moral change is offered. (shrink)

Because reasoning allows us to justify our beliefs and evaluate these justifications it is central to folk epistemology. Following Sperber, and contrary to classical views, it will be argued that reasoning evolved not to complement individual cognition but as an argumentative device. This hypothesis is more consistent with the prevalence of the confirmation and disconfirmation biases. It will be suggested that these biases render the individual use of reasoning hazardous, but that when reasoning is used in its natural, argumentative, (...) context they can represent a smart way to divide labor without loosing epistemic value. (shrink)

In “Mercier and Sperber’s Argumentative Theory of Reasoning: From Psychology of Reasoning to Argumentation Studies” (2012) Santibáñez Yañez offers constructive comments and criticisms of the argumentative theory of reasoning. The purpose of this reply is twofold. First, it seeks to clarify two points broached by Yanez: (1) the relation between reasoning (in this specific theory) and dual process accounts in general and (2) the benefits that can be derived from reasoning and argumentation (again, in this specific theory). Second, (...) it suggests one domain—the categorization of arguments—in which argumentation studies and the argumentative theory of reasoning could usefully complement each other to yield a better understanding of the processes of argumentation. (shrink)

Mercier and Sperber (2011a, 2011b; Mercier, 2011a, 2011b, 2011c, and 2011d) have presented a stimulating and provocative new theory of reasoning: the argumentative theory of reasoning. They maintain that argumentation is a meta-representational module. In their evolutionary view of argumentation, the function of this module would be to regulate the flow of information between interlocutors through persuasiveness on the side of the communicator and epistemic vigilance on the side of the audience. The aim of this paper is (...) to discuss the perspective of the authors in which they conceive this competence as the natural scenario of reflective reasoning. (shrink)

Over the last decade, Hugo Mercier and Dan Sperber have elaborated an influential naturalistic account of human reasoning. Their distinctive hypothesis is that its adaptive rationale – and primary function – is to produce and assess reasons in interpersonal justification and argumentation. In this paper I argue, first, that their characterisation of reasoning as based on metarepresentations threatens to oversophisticate reasoning and faces the problem of vicious regress. Second, I argue that they owe us a coherent account of (...) the cognitive role of reasons in reasoning. (shrink)

This paper aims to accessibly present, and then critique, Hugo Mercier and Dan Sperber's recent proposals for the evolutionary function of human reasoning. I take a critical look at the main source of experimental evidence that they claim as support for their view, namely the confirmation or “myside” bias in reasoning. I object that Mercier and Sperber did not adequately argue for a claim that their case rests on, namely that it is evolutionarily advantageous for you (...) to get other people to believe whatever you antecedently believe. And I give my own argument that this claim is false. I also critically look at their suggestion that reasoning has a justificatory function, functioning as a kind of reputation management tool. I argue this suggestion does not amount to a plausible evolutionary function. (shrink)

The standard view of the function of reason is that it emerged to enable individuals to make better judgements and choices. Once individuals could think better, and once we had suitable communicative tools, individual reasoning acquired a public face; we reasoned together as well as privately, in our own mind. Hugo Mercier and Dan Sperber argue that this gets the story the wrong way around: reasoning evolved for public purposes: to persuade, negotiate, assess. Once it was established publically, (...) perhaps it acquired a private function too. With the exception of a few minor complaints, this evolutionary case is well made. However, Mercier and Sperber embed their evolutionary case within a modular view of the mind and suggest a modular view of public reasoning itself. While I find the evolutionary case persuasive, I am sceptical of the cognitive science framework. (shrink)

Mercier and Sperber illuminate many aspects of reasoning and rationality, providing refreshing and thoughtful analysis and elegant and well‐researched illustrations. They make a good case that reasoning should be viewed as a type of intuition, rather than a separate cognitive process or system. Yet questions remain. In what sense, if any, is reasoning a “module?” What is the link between rationality within an individual and rationality defined through the interaction between individuals? Formal theories of rationality, from logic, probability (...) theory and game theory, while not the focus of Mercier and Sperber's book, may help clarify this latter question. (shrink)

The biological function of human reasoning abilities cannot be to improve shared knowledge. This is at best a side effect. A more plausible function of argumentation, and thus of reasoning, is to advertise one's ability to detect lies and errors. Such selfish behavior is closer to what we should expect from a naturally selected competence.

In The Enigma of Reason, Hugo Mercier and Dan Sperber (2017) defend the proposal that reason is a specialized module which produces intuitions about reasons. Reason serves two functions: for individuals to justify their own judgments and actions to themselves and others, and to persuade others. In this review, I briefly summarize the central claims of the book, critically examine Mercier and Sperber’s arguments that reason is not a general faculty underlying our inferential abilities, and explore (...) the pedagogical implications of their work. (shrink)